This invention pertains to a water conditioning or purifying apparatus and a water treating method, and more particularly to an apparatus of either portable or stationary type for removing harmful substances, especially chlorine, chlorinated carbon-hydrogens, pesticides, herbicides, insecticides, heavy metals and nitrates from tap-water sources for discharging high quality drinking water.
An embodiment of this type of apparatus is distributed by BFS Filtersysteme GmbH, Taunusstein, Germany, as TWF 2000N. It has a casing of plastic material with a cover, a cylindrical shell and a bottom. Within the cover an activated carbon filter rod is provided, which by a combined absorption and filtration effect purifies the tap water passing through the apparatus. For purifying the water activated carbon, which is chemically clean and has been pressed into powder, is used within the filter rod, which carbon removes chlorine, fluor-chloride hydrocarbons (FCKW), herbicides, pesticides, heavy metals and germs. Within the lower part of the apparatus an exchangeable small bag including anion exchanger material is provided, which removes nitrate from the tap water.
An apparatus of this type has essential disadvantages: On the one hand the filter rod is to be exchanged rather often, it is expensive to buy and thus the apparatus is not economic in operation. Furthermore, the filtering effect is not optimum and is not sufficiently effective, because the water to be purified cannot be maintained continuously and over a constant time period under the effect of the activated carbon powder, when the water is passed through the apparatus, because the water approaches the filter rod laterally and flows through the filter rod upwardly so that the distance the water flows within the filter rod depends on the fact whether the water enters the filter rod laterally further below or further above at the shell of the filter rod. Moreover, this type of apparatus has the disadvantage that the correct operation of the small bag comprising anion exchange material for removing the nitrate from the water is to be tested in regular, rather short intervals and is to be replaced repeatedly by a new bag. This also increases the costs for operating the apparatus. If the anion exchange material is to be inserted as a little bag the efficiency also cannot be an optimum, because the water to be purified is not continuously affected by the operation of this material.